Deuteronomy 10:16-21

Circumcise therefore the foreskin of your heart, and be no more stiffnecked. For the LORD your God is God of gods, and Lord of lords, a great God, a mighty, and a terrible, which regardeth not persons, nor taketh reward: he doth execute the judgment of the fatherless and widow, and loveth the stranger, in giving him food and raiment. Love ye therefore the stranger: for ye were strangers in the land of Egypt. Thou shalt fear the LORD thy God; him shalt thou serve, and to him shalt thou cleave, and swear by his name. He is thy praise, and he is thy God, that hath done for thee these great and terrible things, which thine eyes have seen.